Add support for [Constructor, Custom=Wrap]

Source/bindings/templates/methods.cpp

 {##############################################################################}
 {% macro generate_method(method, world_suffix) %}
 {% filter conditional(method.conditional_string) %}
 static void {{method.name}}{{method.overload_index}}Method{{world_suffix}}(const v8::FunctionCallbackInfo<v8::Value>& info)
 {
     {# Local variables #}
     {% if method.has_exception_state %}
     ExceptionState exceptionState(ExceptionState::ExecutionContext, "{{method.name}}", "{{interface_name}}", info.Holder(), info.GetIsolate());
     {% endif %}
     {% if method.number_of_required_arguments %}
@@ skipping 416 matching lines @@
         {{throw_type_error(constructor,
               'ExceptionMessages::notEnoughArguments(%s, info.Length())' %
                   constructor.number_of_required_arguments) | indent(8)}}
         return;
     }
     {% endif %}
     {% for argument in constructor.arguments %}
     {{generate_argument(constructor, argument) | indent}}
     {% endfor %}
     RefPtr<{{cpp_class}}> impl = {{cpp_class}}::createForJSConstructor({{constructor.argument_list | join(', ')}});
-    v8::Handle<v8::Object> wrapper = info.Holder();
     {% if is_constructor_raises_exception %}
     if (exceptionState.throwIfNeeded())
         return;
     {% endif %}
 
+    {% if has_custom_wrap %}

[sof, 2014/03/24 08:16:10]

This isn't complete; the constructor overloads need to arrange for wrap() to be
called (which is what the original CL did.)

[Nils Barth (inactive), 2014/03/24 08:49:11]

I don't follow;
I rearranged the original CL slightly so the wrap() call is used
to initialize wrapper,
separately from the v8SetReturnValue call.

+    v8::Handle<v8::Object> wrapper = wrap(impl.get(), info.Holder(), info.GetIsolate());
+    {% else %}
+    v8::Handle<v8::Object> wrapper = info.Holder();
     V8DOMWrapper::associateObjectWithWrapper<{{v8_class}}>(impl.release(), &{{v8_class}}Constructor::wrapperTypeInfo, wrapper, info.GetIsolate(), {{wrapper_configuration}});

[Nils Barth (inactive), 2014/03/24 03:13:19]

BTW, the custom wrap() means we don't need to call associateObjectWithWrapper,
right?
(I'm following Sigbjørn's CL.)

[haraken, 2014/03/24 03:32:44]

Right. The custom wrap() should be already calling associateObjectWithWrapper.

[Nils Barth (inactive), 2014/03/24 03:33:45]

Got it; self-explanatory, so no comment needed.

+    {% endif %}
     v8SetReturnValue(info, wrapper);
 }
 {% endmacro %}